1. Field of the Invention
The present invention relates to the field of drilling and more particularly to a novel rotary drill having an internal drill bit surrounded by a circular cutter so that the core is pulverized and powderized for removal via a fluid circulation system.
2. Brief Description of the Prior Art
It is the current practice to reinforce existing walls of buildings by drilling a hole from the top of the wall through its height and into the foundation so that a reinforcing rod can subsequently be installed within the hole or bore, followed by retention of the rod to the existing wall construction by a suitable cement, pliable plastic or the like. In the performance of drilling, it is customary to use a circular drill so that a solid core is defined for a prescribed length. Subsequently, the drill is removed so that access can be had to the defined core which is removed as a solid piece. For extremely long holes, the procedure is repeated many times so that the resultant hole is well defined and clear of core fragments or debris. Oftentimes, the core is chopped in an independent procedure, followed by removal in pieces or the like.
Obviously, problems and difficulties are encountered when using such a conventional practice, which stem largely from the fact that repetitive drilling and core or core part removal operations are required in order to prepare the wall with a clear hole for receiving the reinforcing rod and retaining material. Inasmuch as the circular cutting of the core is initially required, followed by later removal of the core with separate equipment, this necessitates a time-consuming and multi-equipment procedure. The core formation and its ultimate removal are done in separate operations employing separate equipment.
Therefore, a long-standing need has existed to provide an economic means for providing a hole in an existing wall or formation which not only defines a core during the drilling operation but simultaneously pulverizes the core and evacuates the material of the core without the necessity of multiple drilling and core-removing steps or procedures. Such a means should be operable simultaneously by the same power equipment and should require a single drilling and pulverizing operation.